Dual-Digital VGA Reduces Solution Footprint By 32%
The MAX2063 from Maxim Integrated Products is the industry’s only fully programmable, multi-state, dual-channel, digital IF/RF variable-gain amplifier (VGA), according to the company. Maxim also calls it an easy to control device that delivers an unparalleled combination of VGA performance, programmability, and component integration.
The VGA is designed to provide unique “rapid-fire” gain selection for four customized attenuation states per path, fast 25-ns digital switching, and very low digital VGA amplitude overshoot/undershoot. Maxim says that it is an ideal choice for the “fast-attack” automatic gain circuits (AGC) found in all 2.5H, 3G, and 4G wireless infrastructure transceivers, including GSM/EDGE, CDMA, WCDMA, LTE, and WiMAX applications.
The MAX2063 can serve as an IF or RF all-purpose VGA, interfacing directly with 50-Ω systems operating over the 50- to 1000-MHz frequency range. Since the stages within each path have their own RF input and RF output, it can be configured to optimize either noise figure (i.e., amplifier configured first within the cascade) or linearity (i.e., amplifier configured last).
In the latter configuration, the cascade yields a total gain range of 31 dB, a maximum gain of 21.3 dB, and a noise figure of only 5.6 dB. The cascaded linearity offers 41 dBm of output third-order intercept point (OIP3), 56 dBm of output second-order intercept point (OIP2), and 19 dBm of 1-dB output compression point (OP1dB) performance.
In receiver applications, this linearity directly enhances the receiver’s immunity to strong blocker signals. Second-order and third-order harmonic distortion (HD2 and HD3) are also limited to –54.8 dBc and –72.9 dBc, respectively. This performance eases the filtering requirements of close-in harmonics and leads to simpler and more cost-effective filter designs, Maxim says.
With the device’s rapid-fire gain selection, users can quickly access any of four customized digital attenuation states without incurring the delays associated with reprogramming the device through the serial peripheral interface (SPI) bus. The digital attenuator I/O is further reduced by a factor of 5 or 2.5 (5 control bits versus 1 or 2, respectively) depending on the number of states required.
The MAX2063 incorporates five unique circuit functions into a single, compact monolithic device. Compared to an equivalent circuit using two MAX2066 VGAs, the new dual VGA reduces the circuit’s overall footprint by 32%. These cost and space savings enable the next generation of wireless infrastructure designs in which transceiver price and density issues are paramount, Maxim says.
Available in a lead-free thin quad flat pack no-leads (TQFN) package, the MAX2063 starts at $6.90 in lots off 1000 and up. Pin-for-pin compatible analog and digital (MAX2062) and analog-only (MAX2064) versions also will be available.
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